BMX legend Dave Mirra, who died in February 2016 of a self-inflicted gunshot, has been diagnosed with chronic traumatic encephalopathy.

CTE, the degenerative brain disease believed to be caused by repetitive hits to the head, has been diagnosed in 90 former NFL players and in former hockey players and wrestlers, among others, but Mirra is the first action-sports athlete to be diagnosed with the disease. It was not immediately clear how advanced Mirra's CTE was at the time of his death.

Mirra was age 41 at the time of his death. According to ESPN, he "endured countless concussions during his BMX career, beginning at a young age."

Mirra began riding BMX professionally in 1992 at 18. At age 19, he was hit by a car, which fractured his skull. He went on to medal in 24 X Games appearances, including consecutively from 1995 to 2005. He retired in 2011.

His wife, Lauren, had his brain examined by Dr. Lili-Naz Hazrati at the University of Toronto. Dr. Hazrati returned a positive diagnosis for CTE for Mirra in March. Currently, CTE can be diagnosed only post-mortem.

"Leading neuropathologists from the U.S. and abroad unanimously confirmed the diagnosis of CTE," according to a spokesperson for the Mirra family.

In an interview with ESPN The Magazine, Lauren Mirra said in the last months of his life, Mirra's personality changed drastically. He became moody and forgetful, and, according to Lauren, "he would repeat conversations and topics to the point where it was obvious to the person he was talking to but not to him. He would dwell on a subject and not want to move on from it."

Shortly before his death, Mirra watched Concussion, the 2015 film starring Will Smith as Dr. Bennett Omalu, the Nigerian pathologist who first discovered CTE in the brain of a football player, but watched only half of the movie, according to Lauren.

Lauren had not heard until CTE until "the last week or two" of Mirra's life, but she doesn't believe Mirra knowing he had CTE while he was alive would have helped him much: "Knowing Dave, he probably wouldn't have chosen to be tested for it. He wouldn't want to sit and dwell on a problem. That's not what he did. He kept moving and progressing in life."

In a statement, Lauren Mirra said:

"We would like to thank our family, friends and the overwhelming number of Dave's fans who have supported us during this difficult time. We ask for your continued support in honoring Dave's legacy and for your patience as we plan to create a platform for CTE awareness and research."

CORRECTION

May. 24, 2016, at 15:57 PM

Mirra died in February 2016. A previous version of this story said he died in April 2016.